c,d=[],[]
for i in range(int(input())):
a,b=map(int,input().split())
c.append(a)
d.append(b)
cd=0
for i in range(len(d)):
cd+=c.count(d[i])
print(cd)#include<bits/stdc++.h>
using namespace std;
int main() {
int x;
cin>>x;
int h[x], g[x];
for(int i = 0; i < x; i++) {
cin>>h[i]>>g[i];
}
int count = 0;
for(int i = 0; i < x; i++) {
for(int j = 0; j < x; j++) {
if(h[i] == g[j]) {
count++;
}
}
}
cout<<count;
}
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